Last night the House of Representatives passed the bill that kept us from going over the so-called “fiscal cliff.” That was a huge story, but it’s already not the hottest daily political tussle that plays out on cable and in the DC press. Last night the House Republicans chose not to pass the bill authorizing funds for the areas heavily damaged by Hurricane Sandy. Peter King is mouthing off about leaving the Republican Party–since he doesn’t get us close to a majority, I’d rather he stay in the GOP and screw things up from the inside rather than give Dems a racist caucus member–and Chris Christie unloaded on John Boehner.

Because their party screwed them and their constituents, the few remaining Congressional Republicans in New York and New Jersey may have a tougher time in the next election. But long-term, Northeastern Republicans are suffering from the same problem facing rural and Southern Democrats: regionalization of the parties and the narrow margins in the House of Representatives.

Compared to the 1960’s through 1980’s, Congress today is a more nasty and brutish place where the careers of members in competitive districts are often short. Members of Congress, particularly Republicans, are probably more ideological today than in, say, the 1980’s. But as realignment in the South has shaken out, and the conservative/liberal axis now closely tracks partisanship, it’s not always the ideological zealotry of members from competitive districts that endangers them in general elections. The problem for most members from competitive districts is that their caucuses need the votes of almost every member, on almost every single issue.

Democrats didn’t just control the House: they dominated it. From 1959 through the end of Democratic leadership in 1994, the Democrats, on average, held a 93-seat majority. With so many votes to spare, Democratic leaders could tolerate weak partisan discipline yet still muster the votes needed to pass their legislative priorities…

In recent elections Republican presidential voters have become more likely to vote for Republicans for Congress. Democratic Congressional candidates won only 4 more districts than Al Gore, only 22 more than John Kerry, and only 14 more than Barack Obama. This development has dramatically changed the House. Now that Congressional results largely track presidential results, there are more safe Republican seats, many of them in the South. As a result, the House now has fewer conservative Southern Democrats. Thus, compared to the era of Democratic dominance, ideology now neatly tracks partisanship in the House. Majorities have fewer opportunities to pick up votes from their ideological allies in the minority caucus, so the majority requires more partisan discipline than Democrats required during their dominance. And now a shift of 50 or so seats affects not the degree of Democratic dominance but control of the House.

The “Hastert Rule,” by which Speakers Dennis Hastert and–until last night–John Boehner would not bring to the floor any bill they couldn’t pass with only Republican votes is a more brazenly partisan practice than what prevailed under Speakers prior to Newt Gingrich. But it’s also a result of their narrower partisan margins compared to those enjoyed by Democratic Speakers from the mid-fifties through the eighties. Undisciplined majorities were a luxury for past Democratic majorities, but a threat to the legislative agendas of today’s narrow Congressional majorities (and barring a huge political shock, this will be as much a dilemma for future Democratic majorities as it is for the current Republican majority).

Northeastern Republicans may take a hit because their increasingly regional party acts mostly on regional interests and not in the national interest. Even in strongly Democratic states there are strong Republican pockets, so just as their are a handful of Southern Democrats there will probably always be a few Northeastern Republicans. But over time, what is probably more likely to lead to the defeat of Republicans in districts like thos of Michael Grimm and Peter King is their party’s continued reliance on their votes for politics and policies popular with rural, evangelical and federal government-hating voters in the South, Appalachia, the Plains and Great Basin, but that are unpopular with voters in New Jersey and New York.